param()

$ErrorActionPreference = "Stop"

$repositoryRoot = Split-Path -Parent $PSScriptRoot
$runtime = [System.Runtime.InteropServices.RuntimeInformation]
$runningWindows = $runtime::IsOSPlatform([System.Runtime.InteropServices.OSPlatform]::Windows)
$runningLinux = $runtime::IsOSPlatform([System.Runtime.InteropServices.OSPlatform]::Linux)

if ($runtime::OSArchitecture -ne [System.Runtime.InteropServices.Architecture]::X64) {
    throw "protoc bootstrap supports x64 only"
}

if ($runningWindows) {
    $asset = "protoc-35.0-win64.zip"
    $expectedHash = "d1cede9e308cc3eb072392af1c02ccae4bdd3d2f374ec2970dbd8cdfdaa91363"
    $executableName = "protoc.exe"
}
elseif ($runningLinux) {
    $asset = "protoc-35.0-linux-x86_64.zip"
    $expectedHash = "a45cda0989c17dd950db55f6fbe1e5814c50fda08e87aa422980ac1f89dddbbc"
    $executableName = "protoc"
}
else {
    throw "protoc bootstrap supports Windows x64 and Linux x64 only"
}

$cacheDirectory = Join-Path $repositoryRoot ".tmp-proto/downloads"
$installationDirectory = Join-Path $repositoryRoot ".tmp-proto/protoc-35.0"
$archivePath = Join-Path $cacheDirectory $asset
$downloadURL = "https://github.com/protocolbuffers/protobuf/releases/download/v35.0/$asset"
New-Item -ItemType Directory -Force -Path $cacheDirectory | Out-Null

$needsDownload = -not (Test-Path -LiteralPath $archivePath)
if (-not $needsDownload) {
    $actualHash = (Get-FileHash -LiteralPath $archivePath -Algorithm SHA256).Hash.ToLowerInvariant()
    $needsDownload = $actualHash -ne $expectedHash
}
if ($needsDownload) {
    Invoke-WebRequest -Uri $downloadURL -OutFile $archivePath
}

$actualHash = (Get-FileHash -LiteralPath $archivePath -Algorithm SHA256).Hash.ToLowerInvariant()
if ($actualHash -ne $expectedHash) {
    throw "protoc archive SHA-256 mismatch"
}

New-Item -ItemType Directory -Force -Path $installationDirectory | Out-Null
Expand-Archive -LiteralPath $archivePath -DestinationPath $installationDirectory -Force

$protocPath = Join-Path $installationDirectory "bin/$executableName"
if (-not (Test-Path -LiteralPath $protocPath)) {
    throw "protoc executable was not extracted"
}

$version = (& $protocPath --version).Trim()
if ($version -ne "libprotoc 35.0") {
    throw "protoc version mismatch: $version"
}

(Resolve-Path -LiteralPath $protocPath).Path